There is a frequent need for material excavation. For example, an excavation of ground may be required to locate and expose an existing underground line, such as a sewer, water, power or telephone line to repair those underground lines. One technique commonly used for such excavation is a mechanical ditch digger or backhoe. However, where the location of the line to be repaired is not know precisely, or where the repair is to be made only in a specific area, the use of mechanical excavating devices often necessitates the excavation of far more of the ground than is necessary. Further, the use of such mechanical excavating techniques can often damage the line. Of course, excavating by hand is always possible, but this approach is becoming ever more expensive with the cost of labor and is relatively slow.
One device which has been developed in an attempt to solve these needs is an air excavation tool disclosed in U.S. Pat. No. 4,936,031 issued Jun. 26, 1990 to Briggs, et al. The tool includes a source of high pressure air which is directed through a device at the material to be excavated, with the air expelled at supersonic velocities. The air penetrates the ground and breaks up the ground for removal by a secondary air flow system. However, a need stills exists for enhanced devices and methods utilizing this or similar basic soft excavation techniques.